Furnace



` May 15, 1928. 1,669,796

' E. G. WEI-:Ks

l FURNACE Filed Jan. 3. 1924 Patented May 15, 1928.

"-UNAITED rSTATES PATENT oFFlcalf mUNDGEonGE wEExs, or DURHAM, ENGLAND, AssIGNoE or oNE-HALF To ELEC- TnIoAL IMPROVEMENTS LIMITED, or LONDON, ENGLAND, a BRITISH confirm. y

FURNACE.

" Luxmann nii-,d January s, 1924,` serial No; 684,228, and nl` Great Britain Januari as, 192s;

This invention consists in improvements in or relating to furnaces employing mechanical Stoker-devices, such as a travelling chain-grate fed from a hopper, and has for its object to preventingress and egress of air from the front or from near the feeding end of the furnace. With mechanical stokers such as are referred to above air passes through the spaces betweenA the hopper and the rate and through the grate itself under the opper. The effect of this is to cause uneven or premature ignition or both uneven and premature ignition of the fuel. In cases where air passes outwards from the furnace the effect is 'to cause sparks and dust to be blown out from the Stoker-front. The first disadvanta e leads to trouble at the clinker dam end o the grate where it is found that the fuel is frequently burned out at the sides and at the middle, while at other parts the fuel is found to pass over the dams only partially burnt out.

According to the present invention, in order to overcome the above disadvantages, there is provided a closure for the :furnacefront and means to supply inert gases to the interior of said closure.

In the preferred form of the invention the chamber for the reception of inert gases ex tends to the back end of the stoker and includes the ash-pit, but is bounded by a partition or the like which prevents direct'access of inert gas to the combustion space of the grate.

It is preferred that the gases shall be supplied at a ressure in excess of that normally prevailing in the furnace under working conditions. The gases can be economically provided by passing lue-gases generated in the furnace back to the space enclosed by the front closure above referred to.

The invention will now be described with reference to the accompanying drawing (largely diagrammatic) which is a sectional elevation of a Stoker to which the invention has been applied. y

The drawing shows a stoker of known type in which the travelling grate is con structed of links 10 on to the upper surface of which fuel is delivered from a hopper 11, the fuel in the hopper being preheated. The furnace operates on forced draught, the air for combustion being passed through to the underside of the links 10 upon which the fuel is burnt. According to this invention the furnace frontV is provided with anenclosing casing 12, conveniently comprising light steel removable doors. The casing 12 if it is not already so constructed is made a `good so as to enclose the feed end of the grate, including the wall of the-hopper 11,

in a substantially gas-tight manner. Inert gases are forced in by a blower 6 of any-preferred type by way of inlet 13 disposed near the front end of the furnace, and fill the space 14 defined at one end by the casing 12 at the feed-end of the grate. The inert gas has also access to the ash-pit 15 and to the space 16 below the upper lap of the grate, but a partition 17 prevents the gas from reaching the links upon which the fuel is burnt. The air for combustion is supplied by the inlets 8 between the partition 17, and the underside of the links. i

.In the absence of the gas-sealed front provided by this invention, air would normally tend to leak through the space between the hopper 11 and the grate links and through the links themselves under the hopper. lhereas in the present example forced draught is employed the leakage would be outwards from the furnace. This leakage is opposed by the inert gases in the space within the casing 12, and if these gases be at a slightly higher pressure than that prevailing in the furnace, inert gas will actually pass into the fire space as indicated by the arrows 18 and 19. The presence of inert gas .at the hopper outlet prevents, or at least minimizes `the risk of pre-ignition of the preheated fuel in the hopper.

The back end of the furnace grate should be sufficiently well sealed to prevent undue leakage of the inert gas past the back of the Stoker into the combustion space. If an existing furnace is not already sealed in a suliicient manner additional sealing means will be provided. i

The inert gases may conveniently be flue accomplished by any conventional form of cooler'7 which may be preferred.

What I claim as my invention and desire to secure by Letters Patent is l. In a furnace, a mechanicalestoker device including a grate, a closure for the furnace front, means cooperatingT with said closure to form a chamber separated from the combustion surface of the grate but ineluding the front end of the grate so as to afford access to the fuel-receiving surface of the grate, a mechanism to supply cool inert gases to the interior of said chamber, said cooperating means comprising a partition forming a baie for the inert gases and preventing the inert `erases from passing directly to the combustion space, said par tition extendingr beneath the combustion section of the grate to the back end thereof.

2. In combination with a furnace having a gas sealed furnace front, n, mechanical stoker device, including a grate, and means arranged to deliver fuel through the furnace front on to the front end of the grate, the fuel bearing surface of the grate dividing the furnace into a combustion space above the grate, and a gas space below the fuel bearing surface. means to supply cool inert gases to the front end of said gas space. and partition means comprising a partition extendingr to the rear end of the grate and positioned to prevent direct access of the inert gases to the combustion space through said fuel bearinfgV surface.

In testimoni` whereof I aflix my signa,- ture.

EDMUND GEORGE WEEKS. 

